Combined long and short wave receiver



Nov. 20, 1934. H. o. ROOSENSTEIN COMBINED LONG AND SHORT WAVE RECEIVER Filed Oct. 1, 1931 iii INVENTOR HANS OTTO ROOSENSTEIN BY 1r6 ATTORNEY Patented Nov. 20, 1934 UNITED STATES COMBINED LON G AND SHORT WAVE RECEIVER Hans Otto Roosenstein, Berlin, Germany, as-

signor to Telefunken lose Telegraphic m.

Application October 1,

Gesellschaft fur Drahtb. 11., Berlin, Germany 1931, Serial No. 566,197

In Germany February 19, 1931 6 Claims.

The present invention relates to an arrangement adapted to receive waves of difierent orders of magnitude.

In Patent No. 1,897,735, issued February 14,

1933, a receiver arrangement has been disclosed adapted to Waves of difierent orders of magnitude, the same being characterized by the feature that a tube provided in the long wave receiver arrangement is designed to be changed over for short wave reception in a super-regenerative circuit scheme. The present invention is concerned with a special form of construction of such an arrangement in this manner that the interruption frequency furnished from the interruption frequency tube is transferred, or fed, to the short wave receiver tube by the same device which insures the regeneration of the last mentioned tube in the long wave circuit arrangement.

The novel features which I believe to be characteristic of my invention are set forth in particularity in the appended claims, the invention itself, however, as to both its organization and method of operation will best be understood by reference to the following description taken in connection with the drawing in which I have indicated diagrammatically one arrangement for carrying my invention into effect.

One embodiment of this idea is illustrated in Fig. 1, wherein 1 denotes the antenna which serves for long wave reception, while 2 the aerial used for short Wave reception. The screen grid tube 3 in the case of long waves acts as a radio frequency amplifier, while by cutting in circuit the condenser 5, by means of the switch 21, upon reception of short waves, it is caused to generate the interruption frequency. I

In order to receive short Waves it is also necessary to place the switch 22 upon the contact 23 with the result that the short wave oscillatory circuit 20, 7, is completed. By the interruption frequency oscillation present in the circuit l5, l6, alternating current potentials of this frequency are induced in the coil 14, and these potentials are fed to the tube 4. by way of the variable condenser 13 and the radio frequency choke coil 8. The latter just like choke coil 18 may be regarded as a short-circuit only for the long waves and for the interruption frequency.

The choke coils 9 and 25, on the contrary, act as practically infinitely high reactances for the interruption frequency and the longer incoming waves. If long waves are to be received with the arrangement then the switch 21 is opened, and switch 22 is placed on contact 24. The tube 3 55 then operates only as a radio frequency amplifier,

and the radio frequency potentials acting across the condenser 16 are readily fed to the grid of tube 4 through the circuit including conductor 30, condenser 31 and switch 22. In this instance, the series arrangement of condenser 13 and coil 14 acts regeneratively as far as tube 4 is concerned.

As a general rule it is necessary that the grid of the apparatus may be connected 2, conventional.

audio amplifier, say, a resistance coupled amplifier. The resistance 11 in the plate lead of tube 4 in this latter instance is the coupling resistance of the first tube of the resistance coupled amplifier.

The operation of the present arrangement will be understood more clearly if the system be considered as comprising a super-regenerative receiver for short waves, the audio frequency output voltage for a following audio frequency arnplifier tube (not shown) being taken 01f across the resistor 11 for both the super-regenerative circuit, and for the long wave receiving system which includes a tuned radio frequency ampli fier followed by a regenerative detector, the output of the regenerative detector being impressed across the resistor 11.

Considering, first, the operation of the system from the viewpoint of the reception of long waves, it is necessary to open switch 21, and connect switch 22 to contact 24 to receive long waves. With these connections made the antenna 1 collects the long Wave signal energy, and the collected energy is impressed upon the tunable input circuit 32 connected between the control grid and cathode of the screen grid tube 3. The anode potential for tube 3 is provided by a battery 33 and lead 34 through the long wave radio frequency choke 26. The tube 4 functions as a regenerative detector, the tuned circuit 15, 16 being connected between the control grid and cathode of tube 4.

The anode circuit of tube 4 includes the audio frequency coupling resistor 11 and the long wave radio frequency choke 9. As stated heretofore the detected output of tube 4 is taken off across the resistor 11 and utilized in any desired manner. The path including the variable condenser 13 and coil 14, inductively coupled to coil 15, provides a regenerative feed-back path between the anode of tube 4 and its cathode circuit. Detection is performed by the condenser 31 and grid leak 25 connected across the input electrodes of tube 4.

To receive short waves, the switch 21 is closed, and the switch 22 is moved into contact with the terminal 23. With these connections made, the short wave signal energy is picked up by the antenna circuit 35 containing coil 2 which is inductively coupled. with the coil '7 disposed in an oscillator circuit of the Hartley type, This oscillator circuit comprises the tube 4 having connected between its anode and its control grid the path including coil 7, the condenser 10, and the second coil 7, this said path being shunted by the variable tuning condenser 20. the point 23 of this tunable circuit is connected through the path includingthe coil 18 and resistor 19, to the cathode lead of. thetube 4. Potential for the anode of the tube 4 is provided through a path which includes battery 33, lead 34, the audio frequency coupling: resistor J51, the interruption frequency choke coil 9 and the short wave radio frequency'choke coil 8.

The tube 3 and its associated circuits now function as a source of interruption frequency energy for the oscillator circuit. Thus, the tunable circuit 15, 16 and the tunable circuit 32 connected between the grid and cathode of tube 3 are resonated to the same desiredinterruption frequency. Potential for the anode of tube 3 is fed through the choke coil 26, and the interruption .-freqt1ency.itself is fed to the oscillator circuit through the path which includes the coil'14, magnetically coupled to coil 15,: and the variable condenser 13 which maybe adjustedto control the amount of super-regeneration.

It is not believed necessary to describe in detail the theory underlying the super-regenerative action since those skilled in the art are well acquainted with such theories. It issufiicient to point out that regeneration beyond the normal point of oscillation into the range of superregeneration is carried out in the oscillator circuit including tube 4 by utilizing interruption frequency to vary the plate potential of tube 4 at the interruption frequency rate. This results in a periodic damping of sustained oscillations, the

it will be apparent to one skilled in the art that my invention is by no means limited to the particular organization shown and described, but that many modifications may be made without departing from the scope of my invention as se forth in the appended claims. What I claim is: v H 1. In combination, in a combined long and short wave receiver, anelectron tube provided with a tunable'input circuit and a tunable output circuit, a second electron tube provided with a pair of input electrodes connected across the tunable output circuit of said first tube, means in the anode circuit of the second tube adapted to couple it to a load circuit, a regenerative feed-back path connected between the anode circuit of the second tube and the tunable output circuit of the first tube, a long wave antenna coupled to the tunable input'circuit of the first tube, a short wave an-' tenna, means for coupling the input and output circuits of the first tube to render the said first tube and its associated circuits capable of producing interruption frequency energy, and means for disconnecting the input electrodes of the second tube from the tunable output circuit of the first tube and instead coupling'the anode and grid of the second tube to the short wave antenna.

2. In combination, means for collecting low frequency signal energy, means for collecting high frequency signal energy, a regenerative amplifier tube having an input circuit coupled to said second named means, means for tuningsaid input circuit to the high frequency energy, a second amplifier tubehaving an input circuit coupled to saidfirst named means including means for tuning said circuit to the low frequency energy, said second amplifier tube also having an output circuit, a feedback connection between the input and output circuits of said second amplifier to cause it to generate oscillations at an interrupting frequency, and additional means coupling the output circuit of said second amplifier to said regenerative amplifier for feeding energy at an interrupting frequency to said regenerative amplifier when receiving said high frequency signal energy.

3. In combination means for collecting low frequency signal energy, an amplifier tube having an input circuit coupled to said means and including means for tuning it to the low frequency signals, an output circuit connected to saidtube, a feedback connection between said input and output circuits to cause said amplifier to generate oscillations at an interrupting frequency, means for collecting high frequency signal energy, a regenerative detector having an input circuit coupled to said last named means and including means for tuning said input circuit to the high frequency signals, and additional means, including a resonant path coupling the output circuits of the said amplifier tube and regenerative detector for feeding energy at an interrupting frequency to said detector when receiving high frequency signal energy.

4. The combination of the preceding claim in which the feedback connection of said amplifier tube includes a switch and condenser connected in series. a g

5. The combination defined in claim 2 in which the output circuit of said regenerative amplifier tube includes a high resistance and choke coil connected-in series, said resistance providing a 1 coupling means adapted to couple said amplifier to a succeeding amplifier.

6. In a radio receiver, the combination of a source of low frequency signal energy, an amplifier tube having an input circuit coupled to said source and including means for tuning it to the low frequency energy, an output circuit connected to said tube,- a feedback connection between said input and output circuits to cause said tube to generate oscillations at an interrupting frequency,

a source of high frequency signal energy, a regenerative detector having an input circuit coupled to said last named source and including means for tuning said input circuit to the high frequency energy and means coupling the output circuit of said amplifier tube to saidv regenerative detector including the series connection of an inductance coil and a variable condenser for feeding energy at an interrupting frequency to said detector when receiving high frequency signal energy, adjustment of said condenser serving to controlv the amount of regeneration in said detector.

HANS OTTO ROOSENSTEIN.- 

